Method of adjustment to the level of the line of contact between the free surface of the metal and the ingot mould in the vertical casting of products of any cross-section

Abstract

The invention relates to a method for adjusting the level of the line of contact between the mold and the free surface of the metal in the vertical continuous casting of products of any cross-section in an ingot-mold, which includes the step of applying to the solidifying metal, by means of an electric circuit surrounding the mold, a periodic magnetic field of variable intensity having a direction substantially parallel to the axis of the mold. According to the invention, the magnetic field applied to the mold is varied over a portion of the periphery of the metal. This can be done by modifying the distance between electric circuit creating the magnetic field and the mold, by changing the vertical positioning of the circuit, or by varying the shape of the profile of the circuit.

What is claimed is: 
     
       1. In the vertical continuous casting of metal products of any cross section in an ingot mold, including the step of applying to the solidifying metal, by means of an electric circuit surrounding the mold, a periodic magnetic field of variable intensity having a direction substantially parallel to the axis of the mold, a method for adjusting the level of the line of contact between the mold and the free surface of the metal comprising varying the applied magnetic field over a portion of the periphery of the metal. 
     
     
       2. A method according to claim 1, wherein the field is varied by varying the distance between the circuit and the ingot mould over a fraction of the periphery of the metal. 
     
     
       3. A method according to claim 1, wherein the field is varied by varying the height position of the circuit relative to the ingot mould over a fraction of the periphery of the metal. 
     
     
       4. A method according to claim 1, wherein the field is varied by varying the shape of the profile of the circuit over a fraction of the periphery of the metal. 
     
     
       5. A method according to claim 2, wherein said distance is increased in order to raise the level of said fraction. 
     
     
       6. A method according to claim 5, wherein said ingot mould is of rectangular cross-section having small sides and large sides, and the increase is made opposite the small sides. 
     
     
       7. A method according to claim 6, wherein increase is between 1 and 2 times the distance between the circuit and the large sides. 
     
     
       8. A method according to claim 3, wherein the varing is of a height at most equal to half the actual height of the circuit. 
     
     
       9. A method according to claim 8, wherein the ingot mould is of rectangular cross-section having small and large sides, and the position of the circuit is varied opposite the small sides. 
     
     
       10. A method according to claim 4, wherein the shape of the profile is varied only over the side of the profile facing the ingot mould. 
     
     
       11. A method according to claim 10, wherein the shape is varied by inclining said side over at least a portion of its length. 
     
     
       12. A method according to claim 11, wherein the inclination is less than or equal to 45° to the vertical. 
     
     
       13. A method according to claim 11, wherein the inclination directs the side of the profile away from the ingot mould. 
     
     
       14. A method according to claim 13, wherein said ingot mold is rectangular having large and small sides, and the inclination is limited to the fraction of length situated towards the bottom of said sides of the profile facing the small sides of the ingot mould. 
     
     
       15. A method according to claim 13, wherein said ingot mold is rectangular having large and small sides, and the inclination is limited to the fraction of length situated towards the top of the sides of the profile facing the large sides of the ingot mould. 
     
     
       16. An apparatus for continuous vertical casting of metal products of any cross section, comprising an ingot mold which contains and which is in contact with solidifying molten metal, and an electric circuit surrounding the mold which constitutes means for applying to the solidifying metal a magnetic field of variable intensity having a direction substantially parallel to the axis of the mold to vary the level of contact between the metal and the mold, said circuit comprising an assembly of elongated removable elements which are variable with respect to the mold and which are electrically interconnected except at a defined point in the circuit, and means located on both sides of said defined point for connection of the circuit to a source of electric current. 
     
     
       17. A circuit according to claim 16, wherein the elements have different lengths and/or profile cross-sections. 
     
     
       18. A circuit according to claim 16, wherein the elements are cooled. 
     
     
       19. A circuit according to claim 16, wherein the elements are located in different planes.